Process for making fibrous material water-repellent

ABSTRACT

COPOLYMERS OF ETHYLENE AND VINYLSILANES CONTAINING HALOGEN ATOMS OR LOWER ALKOXY GROUPS ARE USEFUL AS WATERREPELLENT AGENTS. A PREFERRED APPLICATION OF SAID COPOLYMERS IS THE IMPREGNATION OF FIBROUS MATERIAL WITH SOLUTIONS IN ORGANIC SOLVENT, FOLLOWED BY A HEAT TREATMENT AND A FIXING PROCESS WITH WATER OR STEAM.

United States Patent 3,810,775 PROCESS FOR MAKING FIBROUS MATERIAL WATER-REPELLENT Klaus Uhl, Hofheim, Tauuus, and Klaus Fischer, Kelkheim, Taunus, Germany, assignors to Farbwerke Hoechst Aktiengesellschaft, Frankfurt, Germany No Drawing. Filed Jan. 12, 1972, Ser. No. 217,272 Claims priority, application Germany, Jan. 15, 1971, P 21 01 816.6 Int. Cl. B44d 1/094, 1/44; D06m 15/66 US. Cl. 117-21 9 Claims ABSTRACT OF THE DISCLOSURE Copolymers of ethylene and vinylsilanes containing halogen atoms or lower alkoxy groups are useful as waterrepellent agents. A preferred application of said copolymers is the impregnation of fibrous materials with solutions in organic solvents, followed by a heat treatment and a fixing process with water or steam.

The present invention relates to a process for rendering fibrous material water-repellent.

To obtain a hydrophobic finish of textile materials, fleeces and laminated materials, either polysiloxanes or parafiins are used in most cases. Polysiloxanes are especially preferred for rendering textile hydrophobic, owing to the soft touch thereof. At the same time, they have, however, the disadvantage of lubricating the fibers so that anti-slip behavior, for example in viscose lining material and in woven or knit fabrics made from synthetic fibers, is lessened, quite apart from the fact that polysiloxanes are much more expensive than water-repellent agents on a parafiin basis. Compared to polysiloxanes, paraffins have the drawback of producing a substantially more unfavorable effect on the touch. With regard to synthetic fiber textiles this parafiin touch is particularly unpleasant. Moreover, both product types have the disadvantage of substantially increasing the soiling in dry state, some of them even in moist state. This has an even more negative effect since increasing demands are just being made on the easy-to-care properties of textiles, which, as it is known, also comprise the soiling behavior.

'Owing to its hydrophobic nature, polyethylene should also be mentioned as a water-repellent agent. It appears, however, that polyethylene is very sparingly or not soluble in conventional solvents. Therefore, polyethylene is only suitable for a large-scale use in the textile field if it can be brought into a dispersed form. To be able to prepare dispersions or emulsions, a dispersing or emulsifying agent is, however, required. Dispersing or emulsifying agents, which are compounds having a hydrophilic and a hydrophobic portion in the molecule, however, reduce the hydrophobic effect at any event. For example, polyethylene dispersions which have a molecular weight exceeding 7000 and are used, according to German Auslegeschrift No. 1,235,854, for the crease-proof finish, do not impart hydrophobic properties to the fabrics. These polyethylene dispersions, moreover, have the unpleasant property of aggravating the soil release oftfatty and oily soiling. The unfavorable soil release behavior. has a negative effect on the properties of use of the textiles finished therewith.

This invention therefore comprises a modified polyethylene which can be used in a soluble or dispersed form for the treatment of fibrous material to produce waterrepellent effects according to the hydrophobic nature of polyethylene without adversely affecting the anti-slip behavior, exerting a negative influence on the touch of the fibrous material or increasing the tendency of the substrate to soiling.

It has now been found that excellent hydrophobization effects can be obtained on woven and non woven fibrous material and coated articles having a textile substrate, by applying, to the material, a copolymer having recurring units of the Formula I CH CH (I) and of the Formula II Br I CHg-CH-Si-Rr in which R and R and R each stands for a halogen atoms, preferably a chlorine atom, or a lower alkoxy group, preferably the methoxy or ethoxy group. Especially preferred are copolymers consisting only or, at least, essentially of a unit of the Formulas I and II.

These copolymers have the advantage of being soluble in organic solvents, not deteriorating the anti-slip behavior nor having a negative effect on the touch. The most striking feature of the finish of the invention, however, is that there is no additional tendency to soil observed nor the soil release aggravated. This is surprising since it had to be expected, owing to the silicone-containing groups present in connection with the tendency to soil and the unfavorable soil release behavior of silicones, that these copolymers, too, have an increased tendency to soil.

Copolymers having from about 1 to about 50, preferably about 10 to about 50, percent by weight of units of the Formula II have proved especially effective. It is, moreover, possible to use copolymers which contain further monomers, for example acrylic acid and methacrylic acid and the derivatives thereof, such as the corresponding nitriles, amides and esters, vinyl compounds, styrene and aliphatic monoand diolefins, such as propylene or butadiene. The percentage of these further monomers may amount to about 10 percent by weight, calculated on the whole polymer.

The polymers used according to the invention may be employed in the form of powders, suspensions, dispersions, solutions or gels. They may be prepared by radicalinitiated copolymerization of the corresponding vinyl silanes at temperatures of from about to about 200 C. and under an ethylene pressure of from about 5 to about 700 atmospheres with the use of radical-yielding agents in the absence or presence of diluents and, where required, of substances that control the molecular weight. Ethylene-vinyl-trialkoxy-silane copolymers of the specified type have, for example, been disclosed in US. Pat. No. 3,225,018.

Copolymers of ethylene and vinyl-triethoxy-silane, which are particularly preferred, may be prepared as follows:

In a high-pressure autoclave having a capacity of 2000 parts by volume, a mixture of 200 parts by volume of isopropanol and 16 parts by weight-of vinyl-triethoxysilane is heated to about 160-165" C., pressurized with 700 atmospheres of ethylene at this temperature, and a solution of 0.5 part by weight of di-tert.-butyl peroxide and 46 parts by weight of vinyl-triethoxy-silane in 200 parts by volume of isopropanol is pumped in within about minutes, the ethylene consumption being completed to 700 atmospheres at a level of 680 atmospheres. After pressure release, the polymer obtained is freed from isopropanol and unreacted vinyl-triethoxy-silane. It is also possible to begin with the total amount of vinyl-triethoxysilane or to feed in the total amount of this compound later on.

The compounds to be used acording to the invention may be cross-linked by thermal treatment (cf. US. Pat. No. 3,225,018) or by the action of water.

Depending on the consistency of the substrate, the polymers are applied to the fibrous material according to various coating methods, for example by melting,

powdering, foaming, slop padding or spreading; furthermore, by impregnating, spraying or by the exhaustion methods. The dry cleaning method may also be employed.

For fixation purposes, the textile material treated with the polymer is subjected to a treatment either with steam that may give a neutral reaction or may contain substances which give an alkaline or acid reaction, or with water that has been heated to a temperature of from about 40 to about 90 C., or with aqueous solutions that give an alkaline or acid reaction, or solvents containing water, for example aqueous dimethylformamide solutions, or to an iron or decatizing method in the presence of moisture or to a felting method.

It is also possible to treat the material to be finished with water or steam and to impregnate, coat or spray it with the polymer in moist state, the moist material being heated to temperatures of at least about 40 C.

According to a preferred embodiment of the invention, the polymer is dissolved in solvents, such as for example trichloro-ethylene, perchloro-ethylene, xylene, dimethylformamide or fiuorinated and/or chlorinated lower aliphatic hydrocarbons. The material to be treated is then impregnated with this solution and finally exposed to air or heated to eliminate the solvent. Subsequently, the material is treated with hot water or steam. Depending on the temperature of the medium, this treatment may last from a few seconds to several minutes, but it may also be carried out by a several-hours dwelling of the moist textile material.

Felts, laminated and poromeric material (synthetic leather) are suitably rendered hydrophobic by spraying a solution and subsequently steaming the material. The hydrophobic effects can be achieved on fibrous material made of a great many of fiber types. The fibrous material may be made from natural fibers, for example wool, cotton, jute, from synthetic fibers, for example viscose fibers, cuprammonium-rayon, cellulose acetate fibers, polyester fibers, polyamide fibers, polyacrylonitrile fibers, acrylonitrile copolymers, polyurethanes, polyvinyl chloride, a variety of mixtures of synthetic fibers, of synthetic fibers and natural fibers, furthermore of inorganic fibers, such as asbestos, carbon, quartz or glass fibers or glass fibers in mixture with synthetic fibers.

The water-repellent agents may be used as such or in combination with various finishing and coating agents. Special mention is made of the joint use with creaseproofing products and the catalysts required for crosslinking. The joint use with water-repellent agents on siloxane or parafiin basis, on the basis of modified triazine derivatives and pyridinum halides or textile softeners of hydrophobic nature, for example stearic acid derivatives, is possible. When used together with oil-repellent agents, the hydrophobic effect of these agents is increased. The polymers can moreover be combined with optical brighteners, dyestuffs, including pigment dyestuffs, antistatics, metallizing agents, finishing agents and antimicrobial ingredients. For reinforcing fleeces, felts, tufted felts, spun-bonded material or paper machine fleeces, the polymers can be employed jointly with usual binders, for example polyacrylic acid esters or butadiene copolymers. It is also possible, in the case of non woven material, first to impregnate the fibrous material with the polymer and then apply the binder which serves as a reinforcing agent. This mode of application is of interest, for example, in the reinforcement of distinctly hydrophilic fibers.

The polymers may also serve as a top layer of hydrophobic nature on poromeric material, laminated material, coatings and back finish. Their use for this purpose is especially advantageous since the tendency to soil is not increased. In cases of a porous surface having poor adhesive properties, this tendency to soil is even decreased. The low tendency to soil gains its full importance especially in the case of tufted felts, in particular for floor cover material. In this case, the soil tendency due to the reinforcing agent is successfully reduced. The bydrophobic effect that is simultaneously achieved, moreover, prevents access of moist dirt.

The following examples serves to illustrate the invention the parts, ratios and percentages being by weight unless stated otherwise.

EXAMPLE 1 A cotton fabric was impregnated with a solution of 5 parts of a copolymer of ethylene/vinyl-triethoxy-silane (/20) and parts of perchloro-ethylene, squeezed off and stored for 10 minutes at 50 C. The fabric thus treated was exposed to a steam atmosphere for 30 seconds and dried.

The fabric showed a pronounced hydrophobic effect. Water droplets that hit the fabric were repelled. A dry soiling test using synthetic road dust and a moist soiling test using a mixture of soot, mineral oil and tallow demonstrated that the fabric was not more soiled than the untreated fabric. The touch of the fabric was only slightly changed; the fabric had a somewhat full handle. The treatment with the polymers of the invention did not impair the soil release behavior in comparsion to the untreated material. The test was carried out according to the AATCC test -169.

EXAMPLE 2 A loosely woven wool fabric was impregnated with a solution of 3 parts of a copolymer of ethylene/vinyl-triethoxy-silane (88/ 12) and 97 parts of perchloro-ethylene squeezed off and freed from the solvent by heating it to 60 C. After a decatizing process the fabric showed a good water-repellent effect.

EXAMPLE 3 A fleece made from polyester fibers and coated on one side was sprayed with a solution of 2 parts of a copolymer of ethylenelvinyl-triethoxy-silane (80/20) and 98 parts of perchloro-ethylene. The solvent was eliminated by the action of heat, followed by a steam treatment on an ironing press. The coated fleece was given a hydrophobic layer. Water droplets were repelled.

EXAMPLE 4 20 grams of a copolymer of ethylene and vinyl-triethoxy-silane (80/20) were added, per liter of perchloroethylene, to a dry cleaning bath of perchloroethylene. Articles of clothing made of cotton fabrics and polyestercotton blend fabrics were cleaned with this liquor. Upon a subsequent ironing operation on a press the textiles showed a good water-repellent effect.

EXAMPLE 5 A tufted felt was impregnated with 500 g. of a dispersion of a copolymer consisting of butylacrylate, styrene, acrylonitrile and acrylic amide (52/21/ 25/2) per liter of liquor and sprayed with a solution of 95 parts of perchloroethylene and 5 parts of a copolymer of ethylene/ vmyl-triethoxy-silane (80/20). Fixation was then performed at C. A water drop that hit the surface of the tufted felt gradually spread thereon only after a period of 10 minutes. A dry soiling test using road dust demonstrated a substantially lower degree of soiling than a comparative test on a tufted felt sample that had only been finished with the acrylic ester copolymer dispersion.

We claim:

1. A process for rendering fibrous material water-repellent which comprises contacting said material with a copolymer having recurring units of the formula in which R, R and R are chlorine, methoxy or ethoxy, said copolymer having about 1 to about 50% by Weight of recurring units of Formula II, and fixing said copolymer on said material by steam or heated water.

2. A process as claimed in claim 1, wherein the copolymer contains about to about 50% by weight of recurring units of Formula II.

3. A process as claimed in claim 1, wherein the copolymer contains 12 to 20 %by weight of recurring units of Formula II.

4. A process as claimed in claim 1, wherein the copolymer is dissolved in a solvent of chlorinated hydrocarbon, fluorinated hydrocarbon or fluorinated chlorohydrocarbon.

5. A process as claimed in claim 1, wherein the copolymer is in an aqueous emulsion or dispersion.

6. A process as claimed in claim 1, wherein the copolymer is in powder form.

7. A process as claimed in claim 1, wherein the copolymer is used in combination with a crease-proofing agent or an oleophobic agent.

8. A process as claimed in claim 1, wherein the fibrous material is initially moist and the fixing is carried out at a temperature range of about 40 to about 150 C.

9. A process as claimed in claim 1, wherein a fibrous material of woven, knitted or nonwoven fabrics consisting essentially of fibers selected from the group consisting of cellulose, wool and linear polyesters is impregnated with a solution of 2 to 20% by weight of a copolymer consisting of to 88% by weight of recurring units of the formula and of 20 to 12% by weight of recurring units of the formula 2,893,898 7/1959 Evans et al 1l7-l6l FA 3,629,214 12/1971 Buning et a1 260-80 PS 3,225,018 12/1965 'Futty 260-88.] "R 3,278,476 10/ 1966 Santelli 26080 PS 3,460,981 8/1969 Keiz et al 1062 3,437,509 4/ 1969 Coisne 117-62 WILLIAM D. MARTIN, Primary Examiner M. SOFOCLEOUS, Assistant Examiner US. Cl. X.R.

117-62, 119.8, 65.2, 139.4, 139.5 A, A, 143 A 

